how to make a line break in a text object from an external file
When the text file is read, no interpretation is made of what is written, is just text.
For that reason yo sould write in the text file as: own.text = 'write it in \na new line' and then in your script use exec.
from bge import logic

def text():
    path = logic.expandPath('//')
    cont= logic.getCurrentController()
    scene= logic.getCurrentScene()
    own= cont.owner

    try:
        file = open(path+'text_file.txt', 'r')
        info = file.readlines()
        exec(info[0])
        
    except Exception as e:
        print('error', e)

Disclaimer
CAUTION
This is as dangerous as someone writing &quot;wipeout this pc&quot; and boom... your info is gone!.